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The Respiratory Protection Information Trusted Source										Related Pages
										Respirator FAQsGeneralWhat is an N95 filtering facepiece respirator (FFR)?
	An N95 FFR is a type of disposable respirator where the filtration media is the respirator. The respirator forms a tight seal to the face and removes particles from the air that are breathed through it. These respirators filter out at least 95% of very small (0.3-micron) particles. N95 FFRs are capable of filtering out particles, including bacteria, viruses, and dust.What is the difference between an air-purifying respirator (APR) and atmosphere-supplying respirator (ASR)?
	Air-purifying respirators (APRs) remove gases, vapors, and aerosols (airborne droplets and solid particles) hazards from the air around you (as opposed to providing a separate supply of clean air). However, the appropriate filter media must be selected based on a hazard assessment. For example, while cartridges and canisters can be configured to remove all three of the hazard types, filters can only remove aerosols. These include the following:
Filtering facepiece respirators (FFRs)
Elastomeric half and full facepiece respirators
Powered air-purifying respirators (PAPRs)For more information, see the NIOSH fact sheet, A Guide to Air-Purifying Respirators.

Atmosphere-supplying respirators provide clean breathing air from a source that is independent of the work area. These respirators protect wearers from many types of airborne contaminants (particles, gases, and vapors) and, in certain cases, oxygen-deficient atmospheres. ASRs include the following:
Supplied-air respirators
Self-contained breathing apparatus (SCBA)
Combination Supplied-Air/Self-Contained Breathing ApparatusFor more information, see the NIOSH fact sheet, A Guide to Atmosphere-Supplying Respirators.How do I know what size respirator I need?
	Respirators are available in multiple size configurations and are not standardized across models. Fit testing is needed to determine if a particular size and model of respirator provides you with an acceptable fit. Before you wear a respirator in an occupational setting, you **must be fit tested** for each respirator model you will wear for your designated work tasks.
For more information, see the NIOSH fact sheet, Filtering out Confusion: Frequently Asked Questions about Respiratory Protection, Fit Testing.Respirator TrainingDo I need training to wear a respirator?
	Yes. OSHA regulations require that workplaces provide employees respirator training prior to use in the workplace. It is important that you know what respirator to use and how to use it correctly so that it can provide the expected protection. Refer to OSHA 29 CFR 1910.134external icon for more information.
For more information, see the NIOSH infographic, You’ve just completed your Annual Respirator Training pdf icon.How often do I need respirator training?
	Your employer should provide training at least annually. Additional training may be required when exposure conditions change, when a new type or model of respirator is issued, or when your knowledge or use of the respirator indicates the need (e.g., a supervisor observes improper use of the respirator). Refer to OSHA 29 CFR 1910.134external icon for more information.Respirator UseCan I reuse my filtering facepiece respirator?
	In most workplace situations, a filtering facepiece respirator (FFR) such as an N95 can be reused as part of an employer’s respiratory protection program. Limited reuse refers to the practice of using the same FFR multiple times during a work shift. The respirator is stored between uses and put on again (donned) prior to the next potential exposure for a limited number of donnings. Unless the manufacturer identifies a specified duration of use (for example, “single-use only”) or the employer’s respirator program excludes reuse (for example, when exposed to infectious agents capable of being transmitted by contact), users can wear an FFR until it is damaged, soiled, or causing noticeably increased breathing resistance. FFRs should only be reused by the same wearer and should be stored:
according to the manufacturer’s recommendations,
in a way that protects them from damage (including deforming the straps), dust, contamination, sunlight, extreme temperatures, excessive moisture, damaging chemicals, and
in a way that prevents deformation of the facepiece and exhalation valve.For more information, see the NIOSH fact sheet, Filtering out Confusion: Frequently Asked Questions about Respiratory Protection, Respirator Reuse and Extended Use.How many times can I reuse my filtering facepiece respirator (FFR)?
	Regardless of the setting, the number of times you can reuse an FFR should be limited. Consult the FFR manufacturer for specific guidance regarding reuse and storage of the product.
Extra caution should be taken in certain workplaces where additional risks are posed by handling a used or potentially contaminated respirator. For example, some pathogens such as those found in healthcare settings and biosafety labs can remain infectious on the surface of the respirator for extended periods of time.
In some non-emergency situations (e.g., close contact with patients with tuberculosis) N95 FFR reuse has been recommended in healthcare settings and is commonly practiced (see TB Respiratory Protection Program In Health Care Facilities – Administrator’s Guide).
For more information, see the NIOSH fact sheet, Filtering out Confusion: Frequently Asked Questions about Respiratory Protection, Respirator Reuse and Extended Use.How long can I wear the same filtering facepiece respirator (FFR)?
	Extended use refers to the practice of wearing the same FFR for repeated exposures without removing the respirator. In general, you can safely wear the same FFR until it is damaged, soiled, or causing noticeably increased breathing resistance. Check with your respiratory protection program manager for additional guidance.
For more information, see the NIOSH fact sheet, Filtering out Confusion: Frequently Asked Questions about Respiratory Protection, Respirator Reuse and Extended Use.How do I don (put on) and doff (take off) my respirator?
	Refer to the manufacturer’s instructions for guidance on how to properly don and doff your respirator. The NIOSH-Approved Particulate Filtering Facepiece Respirators webpage provides manufacturer’s donning procedures for most filtering facepiece respirator models.
For more information, see the NIOSH infographic, How to Properly Put On and Take Off a Disposable Respirator.Expired RespiratorsHow do I know if my respirator is expired?
	NIOSH does not require approved filtering facepiece respirators (FFRs) be marked with a shelf life date, although some manufacturers do include them. If an FFR manufacturer does not include information about the product’s shelf life on the product packaging or user instructions, you should seek guidance from the specific manufacturer on whether time and storage conditions (such as temperature or humidity) are expected to have an effect on the respirator’s performance. Manufacturers of respirator cartridges, canisters, and other respirator components may also include shelf-life information on these products, the product packaging, or user instructions.Can I use a NIOSH-approved respirator past the expiration date?
	If there is an expiration date designated by the NIOSH approval holder (i.e., respirator manufacturer) and it has been exceeded, it should not be used within an occupational respiratory protection program. Respiratory protective devices that have passed their expiration date are no longer considered NIOSH-approved for use in occupational settings.How many hours/minutes per shift can I wear a mask without a break?
	Contact your occupational safety and health organization for guidance on respirator use and rest breaks during working hours. There are not currently U.S. regulations mandating breaks related to personal protective equipment. Contact OSHA for additional guidance https://www.osha.gov/contactusexternal icon.
For more information, see the NIOSH Science Blog, The Physiological Burden of Prolonged PPE Use on Healthcare Workers during Long Shifts, for additional information.Respirator SelectionHow do I select a respirator for use in a specific environment?
	An employer is responsible for selecting an appropriate respirator for potential workplace hazards. An employer’s designated respiratory protection program administrator is responsible for ensuring proper respirator selection. The administrator oversees the respiratory protection program at your workplace according to the Occupational Safety and Health Administration (OSHA) respiratory protection standard at (29 CFR 1910.134).
The following resources are helpful when selecting a respirator:
NIOSH Respirator Selection Logic
Types of Respiratory Protection
NIOSH Pocket Guide to Chemical Hazards
OSHA Respirator Protection Training Videoexternal iconsWhat respirator can I wear if I have facial hair?
	Tight-fitting respirators require your face to be clean shaven where the respirator’s seal comes in contact with your skin. If your facial hair does not extend far enough to interfere with the respirator’s seal in any way or interfere with the function of the exhalation valve (if a valve is present on your respirator), you may wear it with the approval of your respiratory protection administrator.
Loose-fitting respirators, such as powered air-purifying respirators (PAPRs) with loose-fitting hoods, do not form a tight seal with the face and, therefore, do not require you to have a clean-shaven face. Loose-fitting air-purifying respirators (i.e., respirators with loose-fitting hoods or helmets) may be worn with any style of facial hair and do not require fit testing.
The following resources are helpful in determining whether a respirator can be worn by those with facial hair:
Facial Hairstyles and Filtering Facepiece Respirators (Infographic)pdf icon
NIOSH Respirator Approval Program’s updated position regarding facial hair and the selection and use of respiratory protective devices (NIOSH CA 2018-1005R1.0)
To Beard or not to Beard? That’s a good Question! (NIOSH Science Blog)End-of-service-lifeWhat does end-of-service-life mean?
	End-of-service-life is when a respirator no longer works correctly. The respirator no longer provides you the expected level of protection from harmful contaminants.Do APRs have indicators or end-of-service-life indicators on them?
	Some APRs have indicators to make the user aware when it is reaching the end of its service life. For example, chemical cartridges may have a color-changing indicator to let the user know when to replace their cartridge. For filtering facepiece respirators, however, the “indicator” may just be the appearance—whether the respirator is damaged, contaminated with visible blood or body fluids, or misshapen.Do ASRs have alarms or end-of-service-time indicators on them?
	SCBAs are equipped with warning devices such as alarms, commonly referred to as end-of-service-time indicators (EOSTI), that tells you when the breathing air provided by the respirator is close to depletion. NIOSH evaluates these warning devices to ensure they activate at the proper remaining service time or pressure.How can I determine when I should change the cartridge/canister if my APR does not have an end-of-service-life indicator?
	The service life of a cartridge/canister depends upon many factors including environmental conditions, breathing rate, filtering capacity, and the type and concentration of contaminants in the airexternal icon. Filtering capacity is based on many product-specific criteria. Therefore, most manufacturers provide information on their websites to help determine the appropriate changeout schedule for their individual products that considers all of these factors.
It is important that you follow the manufacturer’s guidance. Consult your respirator program administrator for additional guidance on determining changeout schedules.
The following resources are helpful in determining changeout schedules:
NIOSH MultiVaporTM Version 2.2.5 Application
OSHA Respiratory Protection eToolexternal icon
OSHA Respiratory Protection eTool- Advisor Geniusexternal icon**Additional Resources**NIOSH Documents
	NIOSH Respirator Selection Logic (2004)
Filtering out Confusion: Frequently Asked Questions about Respiratory Protection, Respirator Reuse and Extended Usepdf icon (2018)NIOSH Infographics
	Key Resources of a Respiratory Protection Programpdf icon (2015)
You’ve just completed your Annual Respirator Trainingpdf icon (2016)
Facial Hairstyles and Filtering Facepiece Respiratorspdf icon (2017)
What are Air-Purifying Respirators?pdf icon (2017)
What are Atmosphere-Supply Respirators?pdf icon (2019)
Types of Respiratory Protectionpdf icon (2019)NIOSH Blogs
	N95 Day 2016: Proper Use, Filtration, and Fit – The Three-Legged Stool of Respiratory Protection (2016)
To Beard or not to Beard? That’s a good Question! (2017)
I Will Survive! Air-Purifying Respirator Cartridge/Canister (2018)
N95 Day 2018: Getting Down to the Particulars about Filter Class (2018)NIOSH Webpages
	NIOSH Pocket Guide to Chemical Hazards
Elastomeric Half Mask Respirator Resources
							
					
						Page last reviewed:  September 3, 2021					Content source: 	National Institute for Occupational Safety and Health homeNPPTL
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